Shaft coupling structure

Abstract

In a shaft coupling structure in which a second shaft is inserted into a cylindrical portion provided in a first shaft to be coupled with each other, with a bush being interposed between an inner circumference of the first shaft and an outer circumference of the second shaft, the first shaft and the second shaft are coupled with each other by a combination of a key coupling and a clamp coupling; the first shaft has a keyway with which the key engages and a shaft slit which is formed in the cylindrical portion by cutting off a portion thereof in the axial direction; and a fastener for the clamp coupling is mounted on a portion of an outer circumference of the first shaft in which the shaft slit is formed and the bush has a bush slit which corresponds to the keyway.

What is claimed is: 
     
       1. A shaft coupling structure in which a second shaft is inserted into a cylindrical portion provided in a first shaft to be coupled with each other,
 wherein, with a bush being interposed between an inner circumference of the first shaft and an outer circumference of the second shaft, the first shaft and the second shaft are coupled with each other by a combination of a key coupling and a clamp coupling, 
 wherein the first shaft has a keyway for the key coupling which a key engages and a shaft slit which is formed in the cylindrical portion by cutting off a portion thereof in an axial direction, 
 wherein a fastener for the clamp coupling is mounted on a portion of an outer circumference of the first shaft in which the shaft slit is formed, 
 wherein the bush has a bush slit which corresponds to the keyway, and 
 wherein, after the clamp coupling is completed, the bush slit of the bush has a width larger than a width of the keyway of the first shaft. 
 
     
     
       2. The shaft coupling structure according to  claim 1 ,
 wherein a single groove serves both as the first keyway of the first shaft and the shaft slit. 
 
     
     
       3. The shaft coupling structure according to  claim 1 ,
 wherein, even after the clamp coupling is completed, the keyway of the first shaft has a width larger than a width of the key. 
 
     
     
       4. The shaft coupling structure according to  claim 1 ,
 wherein the first shaft has a plurality of the shaft slits, and the bush has only one bush slit. 
 
     
     
       5. The shaft coupling structure according to  claim 1 ,
 wherein the bush has a plurality of the bush slits, and at least two bush slits have axial lengths different from each other. 
 
     
     
       6. The shaft coupling structure according to  claim 5 ,
 wherein, among the plurality of bush slits, one bush slit is formed to pass through the bush in the axial direction. 
 
     
     
       7. The shaft coupling structure according to  claim 1 ,
 wherein the second shaft has a second keyway with which the key engages, and 
 wherein the key engages with the keyway of the shaft and the second keyway of the second shaft. 
 
     
     
       8. The shaft coupling structure according to  claim 1 ,
 wherein 
 the first shaft, with different sizes of the bush, is configured to accommodate different sizes of the second shaft. 
 
     
     
       9. A shaft coupling structure in which a second shaft is inserted into a cylindrical portion provided in a first shaft to be coupled with each other,
 wherein, with a bush being interposed between an inner circumference of the first shaft and an outer circumference of the second shaft, the first shaft and the second shaft are coupled with each other by a combination of a key coupling and a clamp coupling, 
 wherein the first shaft has a keyway for the key coupling which a key engages and a shaft slit which is formed in the cylindrical portion by cutting off a portion thereof in an axial direction, 
 wherein a fastener for the clamp coupling is mounted on a portion of an outer circumference of the first shaft in which the shaft slit is formed, 
 wherein the bush has a bush slit which corresponds to the keyway, 
 wherein the bush has a plurality of the bush slits, and at least two bush slits have axial lengths different from each other, 
 wherein, among the plurality of bush slits, one bush slit is formed to pass through the bush in the axial direction, and 
 wherein, among the plurality of bush slits, the bush slits which do not pass through the bush have axial lengths longer than an axial length of the fastener. 
 
     
     
       10. The shaft coupling structure according to  claim 9 ,
 wherein a single groove serves both as the keyway of the first shaft and the shaft slit. 
 
     
     
       11. The shaft coupling structure according to  claim 9 ,
 wherein, even after the clamp coupling is completed, the keyway of the first shaft has a width larger than a width of the key. 
 
     
     
       12. The shaft coupling structure according to  claim 9 ,
 wherein the first shaft has a plurality of the shaft slits, and the bush has only one bush slit. 
 
     
     
       13. The shaft coupling structure according to  claim 9 ,
 wherein the second shaft has a second keyway with which the key engages, and 
 wherein the key engages with the keyway of the shaft and the second keyway of the second shaft. 
 
     
     
       14. The shaft coupling structure according to  claim 9 ,
 wherein the first shaft, with different sizes of the bush, is configured to accommodate different sizes of the second shaft.